1. Field of the Invention
The present invention relates to a method of controlling temperature and a plasma processing apparatus.
2. Description of the Related Art
A plasma processing method is proposed of placing a wafer on an electrostatic chuck having a preliminarily set high temperature and processing the placed wafer with plasma in order to enhance performance of the plasma processing. According to this method, there occurs a thermal expansion difference between the wafer and the electrostatic chuck due to the temperature difference between the wafer and the electrostatic chuck generated when the wafer is placed on the electrostatic chuck having the preliminarily set high temperature. As a result, sometimes a back surface of the wafer is rubbed against the electrostatic chuck, and particles are generated from the back surface of the wafer.
Therefore, as disclosed in Japanese Laid-Open Patent Application Publication No. 2000-12664, a method is proposed of controlling the thermal expansion difference between the wafer and the electrostatic chuck so as to be within a predetermined range by making the difference between the temperature of the wafer before being placed on the electrostatic chuck and a maximum temperature of the wafer after being placed on the electrostatic chuck a preliminarily set temperature or lower, thereby preventing the generation of the particles.
However, in the method disclosed in Japanese Laid-Open Patent Application Publication No. 2000-12664, the object to be processed needs to be heated in a preliminary heating chamber in order to set the temperature difference within the predetermined temperature range. As such, an apparatus structure and process become complicated.